A stud type base of a semiconductor device comprises a base body of thermally and electrically conductive material such as copper or copper alloy having a raised portion provided on the upper surface to mount a semiconductor pellet thereon and a stud provided on the lower surface to be threaded. A shell having a hermetically sealed glass terminal or terminals is projection welded to the base on the upper surface so that the semiconductor pellet is covered, with the hermetically sealed glass terminal or terminals being connected to the semiconductor pellet. In order to accomplish this, the base is generally provided on the upper surface with a metal ring of weldable material such as iron or steel silver soldered thereto, with the metal ring having an annular projection provided thereon. In the prior art, such a base has been manufactured by silver soldering to a base body of copper or copper alloy, an iron or steel ring having an annular projection formed by cutting. Otherwise, it has been manufactured by silver soldering an iron or steel ring to a base body of copper or copper alloy and then cutting the metal ring to form an annular projection thereon. However, in these prior methods, two separate steps are required for forming the annular projection on the metal ring and extruding the base body and cause the manufacturing cost to be high. Another important disadvantage is that the strength of the bond of the iron or steel ring to the base body has been low due to a difficulty in transferring the silver of the solder to the iron of the ring during silver soldering the metal ring to the base body. Thus, the iron ring tends to come loose from the base body after the semiconductor device has been used for a long time.